Enclosures for vegetation are found in a wide range of sizes. The largest are large-volume commercial green houses that can cover several acres and the smallest have volumes in the range of several cubic centimeters. All of them are intended to provide a controlled or protected environment for plant growth, such as allowing year-round growth where the enclosures are temperature controlled, providing a passively solar-heated environment in early or late growing seasons when frost is a threat, providing protection from weather extremes, or providing protection from harmful airborne organisms, insects and other pests. The type of access incorporated into these enclosures is typically determined by their size and purpose. Green houses that cover more than 10 square meters are usually a walk-in type enclosure whereas enclosures where the entire growing area can be reasonably reached from the outside of the enclosure have some type of access panel or sheet and are often limited in height to one to two meters. These types of enclosures are very often constructed of flat panels with access doors that swing out. Other compact configurations are in the form of a cold frame in which access to small plants is achieved by removing the entire enclosure. In locations where access spaces are limited, such as balconies, the enclosure may only be accessible from one side and in windy locations, such as rooftops, cubic enclosures with hinged access panels can be impractical. This type of construction can also add to the cost of the enclosure and rely on metal frame construction that can reduce the effective insulative properties of the panels.
Several patents issued for greenhouses and plant enclosures address versatility and economy. Means for constructing and expanding light-weight and portable greenhouses of various sizes and configurations is presented in U.S. Pat. No. 6,892,743. Another patent, U.S. Pat. No. 2,691,848 describes a small, frameless plant protector. U.S. Pat. No. 7,036,270 describes a mobile application. Quonset-type semi-cylindrical construction has been long recognized as an economical and durable building concept, particularly in harsh weather conditions, and is applied to walk-in greenhouses in U.S. Pat. No. 5,333,421. Similarly, a form of walk-in greenhouse or sunroom with an overall quarter-cylinder shape intended to be located against a wall or other vertical structure is described in U.S. Pat. No. 4,018,213. Since some form of insulation is a desirable feature for greenhouses in many climates, insulative transparent or translucent corrugated and double-wall plastic sheets that are flexible enough to conform to the curved frame of a semi-cylindrical plant enclosure are commonly used. However, they typically have a bending radius not small enough to accommodate compact plant enclosures.
Patents have also been issued which include means of plant enclosure access without relying on swinging doors or panels. One configuration presented in U.S. Pat. No. 4,051,626 utilizes horizontally sliding access panels. A method applied to compact semi-cylindrical greenhouses as shown in U.S. Pat. No. 4,671,011 has a split cover with one half side on a hinge such that it can be rotated open exposing half the enclosed space. This patent additionally describes a form of the invention which is modular with a rotating cover for each of the modules in series. Another method for accessing a low-profile semi-cylindrical greenhouse is to simply lift or fold open the transparent sheet that forms the skin of the greenhouse as shown in U.S. Pat. No. 6,185,877. This method is simple and economical, but the sheet covering can deform fairly quickly and tends to have poor insulating qualities. Another similar method for accessing semi-cylindrical greenhouses is presented in U.S. Pat. No. 6,282,834, except that in this invention, a mechanism is utilized to roll up an insulating sheet. Yet another method for rolling up the greenhouse covering using a framed sheet that rides in grooves in the greenhouse structure is described in U.S. Pat. No. 5,216,834. In the cases where the roof covering is a sheet that can be rolled up, a dedicated mechanism is required to support the sheet. A method for eliminating such mechanisms is to form the cover with a material that is rigid, thus self-supporting, in the horizontal direction but flexible along the curve of the enclosure. A familiar example is a tambour door as utilized in a roll-top desk or a chest as described in U.S. Pat. No. 5,494,181.
The present invention addresses the problem of potential damage or dislocation by high winds or storms by incorporating a curved shape to the upper portion which allows stability in high winds when the back of the enclosure is located against a wall or two identical enclosures are located back-to-back, while also providing the possibility of more vertical internal space for a given floor area than what is possible with a quarter-cylinder or semi-cylindrical form.
The present invention addresses the problem of limited access clearance by eliminating rigid swinging access panels.
The present invention addresses the issue of access relying on covers that require extra dedicated structural elements by incorporating sliding panels that are flexible in a longitudinal direction and generally rigid and restrained in a lateral direction such that they add structural stability to the plant enclosure frame.
The present invention addresses the issue of enclosure insulation by providing means of construction using insulating translucent access panels with a small bending radius, insulating translucent fixed panels and non-metallic framing.
The present invention addresses the issues of enclosure system cost and complexity by incorporating all desirable features in very few elements that can be produced entirely from inexpensive materials, including, but not limited to, polycarbonate, polyethylene, polypropylene, PVC, and recycled forms of these plastics.
Another form of the present invention also addresses the issues of enclosure system cost and complexity by providing a means of multiplying the effective width of an enclosure.